File.SetLastAccessTimeUtc(String,DateTime)是一个内置的File类方法,该方法用于以协调世界时(UTC)设置最后一次访问指定文件的日期和时间。
句法:
public static void SetLastAccessTimeUtc (string path, DateTime lastAccessTimeUtc);
参数:该函数接受两个参数,如下所示:
- path: This is the file for which to set the access date and time information.
- lastAccessTime: This is the specified last access date and time, expressed in UTC time.
例外情况:
- ArgumentException:路径是长度为零的字符串,仅包含空格,或者由InvalidPathChars定义的一个或多个无效字符。
- ArgumentNullException:路径为null。
- PathTooLongException:指定的路径,文件名或两者都超过系统定义的最大长度。
- FileNotFoundException:找不到指定的路径。
- UnauthorizedAccessException:调用者没有所需的权限。
- NotSupportedException:路径格式无效。
- ArgumentOutOfRangeException: lastAccessTime指定一个超出此操作允许的日期或时间范围的值。
下面是说明File.SetLastAccessTimeUtc(String,DateTime)方法的程序。
程序1:在运行下面的代码之前,将创建一个文件file.txt ,其内容如下所示:
C#
// C# program to illustrate the usage
// of File.SetLastAccessTimeUtc() method
// Using System and System.IO namespaces
using System;
using System.IO;
class GFG {
public static void Main()
{
// Specifying a file
string myfile = @"file.txt";
// Calling the SetLastAccessTimeUtc() function
// to set last access date and time
File.SetLastAccessTimeUtc(myfile, new DateTime(2020, 5, 4, 4, 5, 7));
// Getting the last access date and time
DateTime dt = File.GetLastAccessTimeUtc(myfile);
Console.WriteLine("The last access date and "+
"time in UTC for this file was {0}.", dt);
}
}
C#
// C# program to illustrate the usage
// of File.SetLastAccessTimeUtc() method
// Using System and System.IO namespaces
using System;
using System.IO;
class GFG {
public static void Main()
{
// Specifying a file
string path = @"file.txt";
// Checking the existance of the file
if (!File.Exists(path)) {
File.Create(path);
}
// Calling the SetLastAccessTimeUtc() function
// to set last access date and time
File.SetLastAccessTimeUtc(path, new DateTime(2019, 5, 4, 4, 5, 7));
// Getting the last access date and time
DateTime dt = File.GetLastAccessTimeUtc(path);
Console.WriteLine("The last access date and time "+
"in UTC for this file was {0}.", dt);
}
}
输出:
The last access date and time in UTC for this file was 5/4/2020 4:05:07 AM.
程序2:最初没有创建文件。下面的代码本身创建了一个文件file.txt并显示了上次访问的日期和时间。
C#
// C# program to illustrate the usage
// of File.SetLastAccessTimeUtc() method
// Using System and System.IO namespaces
using System;
using System.IO;
class GFG {
public static void Main()
{
// Specifying a file
string path = @"file.txt";
// Checking the existance of the file
if (!File.Exists(path)) {
File.Create(path);
}
// Calling the SetLastAccessTimeUtc() function
// to set last access date and time
File.SetLastAccessTimeUtc(path, new DateTime(2019, 5, 4, 4, 5, 7));
// Getting the last access date and time
DateTime dt = File.GetLastAccessTimeUtc(path);
Console.WriteLine("The last access date and time "+
"in UTC for this file was {0}.", dt);
}
}
执行中:
The last access date and time in UTC for this file was 5/4/2019 4:05:07 AM.